Towers for wind power plants, especially if they are very high, are very often built as so called hybrid towers, in which a lower tower section made of concrete and an upper tower section made of steel are placed on top of the tower section made of concrete.
This hybrid construction method makes it also possible to erect towers with a considerable hub height, which would require a very large wall thickness in the foot if built purely of steel, applying a relatively easy construction method because the diameter of a tubular steel tower is limited owing to transportation reasons. In this context, connecting the tower section made of steel with the tower section made of concrete is important because an optimal bearing load in the concrete must be ensured and damage to the concrete caused by stresses bearing on it must be prevented. Various options have been made known in the state of the art for connecting the steel section with the concrete section.
EP 1 654 460 B1 provides for casting a lower area of the tower section made of steel directly in the tower section made of concrete. To achieve this, the cast terminal area of the tower section made of steel has anchoring elements that protrude radially from the wall of the tower section. Several anchoring elements are provided along the height of the cast terminal area so that the applied loads can be distributed across the entire embedding area.
DE 20 2006 009 554 U1 provides a special adapter element made of steel that is largely ring-shaped and in which, in turn, anchoring elements extending in radial direction are arranged on the inner surface area of the annular steel adapter element. As a result of this, a direct deviation of traction forces without deflection should be allowed in the concrete body.
The disadvantage in connecting the steel tower with the concrete tower lies in the fact that when building the tower section of concrete, the steel tower with its especially developed terminal area or at least the especially developed adapter element must already be available so it can be cast in the tower section made of concrete.
The task of the present invention is to suggest a tower with an adapter element to allow a simple and flexible building of the tower with a good bearing load. Furthermore, a corresponding method should be suggested.